So You Want to Learn a Little Logic
This collection of screencasts that teaches formal logic and assume no prior knowledge. The target audience is both students who are taking an introductory course in formal logic, and people who just have an interest in logic and argumentation. This series is also available as a blog and as a podcast.
Section A: Basic Concepts
In this section, we look at the basic concepts of logic such as soundness, validity and invalidity. We also introduce an informal test for invalidity that you can start using right away to help you spot invalid arguments.
Part 1: Introduction
Part 2: Soundness and Validity
Part 3: Invalidity
Part 4: The Invalidity Test
Supplementary Logic Tutorials
The following videos are a collection of screencasts that show how to use some rules in natural deduction. These videos will eventually be displaced by the "So You Want to Learn a Little Logic" series (above).
Negation Introduction/Elimination
Conditional Introduction
Disjunction Introduction
Disjunction Elimination
Universal Introduction
Existential Elimination